Alex, this is the solution to the exercise:
If the original amount is 320 and the end amount is 112, this is a decrease.
Now, let's estimate the percentage, as follows:
• Difference = Original amount - End amount
,
• Difference = 320 - 112
,
• Difference = 208
In consequence,
• Percentage of decrease = Difference/Original amount * 100
,
• Percentage of decrease = 208/320 * 100
,
• Percentage of decrease = 0.65 * 100
,
• Percentage of decrease = 65%